Background Since the 1990-1991 Persian Gulf War, there has been persistent concern that U.S. war veterans may have had adverse health consequences, including higher-than-normal mortality.

Methods We conducted a retrospective cohort study of postwar mortality according to cause among 695,516 Gulf War veterans and 746,291 other veterans.

The follow-up continued through September 1993.

A stratified, multivariate analysis (with Cox proportional-hazards models) controlled for branch of service, type of unit, age, sex, and race in comparing the two groups.

We used standardized mortality ratios to compare the groups of veterans with the general population of the United States.

Results Among the Gulf War veterans, there was a small but significant excess of deaths as compared with the veterans who did not serve in the Persian Gulf (adjusted rate ratio, 1.09 ; 95 percent confidence interval, 1.01 to 1.16).

The excess deaths were mainly caused by accidents (1.25 ; 1.13 to 1.39) rather than disease (0.88 ; 0.77 to 1.02).

The corresponding rate ratios among 49,919 female veterans of the Gulf War were 1.32 (0.95 to 1.83) for death from all causes, 1.83 (1.02 to 3.28) for accidental death, and 0.89 (0.45 to 1.78) for death from disease.

In both groups of veterans the mortality rates were significantly lower overall than those in the general population.